Synthetic rubber tile with thermal resistance modulation

ABSTRACT

A prefabricated tile-type coating, whose manufacture is based on the development of a polymeric composite including mainly recycled synthetic rubber obtained from the grinding of scrap automotive waste tires, virgin rubber, or a combination of both, using as a binder a novel cross-linkable acrylic resin with the ability to be processed by pultrusion. The upper layer of the tile is made of a resin with thermochromic effect that integrates an encapsulated pigment of thermochromic material with a transition temperature in the range of 20-35° C. which changes color from white under high-temperature conditions, i.e. ° C. or greater than dark in conditions of low temperature, that is, 20° C. or less. The tile of elastomeric character obtained has notable competitive advantages compared to other technologies in terms of thermal resistance, solar reflectance, and resistance to the impact caused by hail or other meteorological phenomena.

OBJECT OF THE INVENTION

The present invention describes a prefabricated tile-type coating, in which the manufacture method is based on the development of a polymeric composite composed mainly of recycled synthetic rubber obtained from the grinding of scrap automotive waste tires, virgin rubber or a combination of both, utilizing as a binder, an innovative retractable acrylic resin with the ability to be processed by pultrusion.

The upper layer of the tile is a resin with thermochromic effect that integrates an encapsulated pigment of thermochromic material with a transition temperature in the range of 20-35° C. which changes color from white under high-temperature conditions, meaning, 35° C. or greater to darker color in conditions of low temperature, that is, 20° C. or less.

The tile of elastomeric character obtained has notable competitive advantages compared to other technologies regarding thermal resistance, solar reflectance, and resistance to the impact caused by hail or other meteorological phenomena.

BACKGROUND

The manufacture and commercialization of asphalt coatings of the roof tile type or “Bitumen Shingles” by its denomination in English, has been carried out during the last 50 years and has consolidated as a robust and economic technology that is commercialized worldwide but mainly in the United States of America. This product includes a cellulose body impregnated with modified asphalt and superficially covered by gravel in different colors and textures. Although this product has market acceptance, it has functional deficiencies such as the volatilization and degradation of certain low-boiling oily components responsible for the plasticity of the product that seriously affects its mechanical properties, rendering the texture of the asphalt tile, hard and brittle, resulting in cracks and markedly lower impact resistance, which becomes evident when meteorological phenomena such as hail breaks the tile causing leaks, and the need to replace it.

On the other hand, the traditional asphalt tile does not offer any thermal resistance in the ceilings, to the contrary, the asphalt has a high thermal conductivity resulting in the inability to reduce the flow of heat to have external temperatures of 35° C. or greater or increase it when having external temperatures of 20° C. or lower and provide some thermal comfort to the user. The manufacturers of this roof-tile type prefabricated coating have made great efforts to provide a heat transfer reduction effect or a thermal resistance effect. These efforts have been oriented towards the development of covers of high reflectance and high emissivity on the tile asphaltic as is shown in United States Patent Application 2004/0009319, in which surface coatings of the polymeric type with high emissivity and reflectance are promoted, such as Polyvinylidene Fluoride (PVF) films, as well as promoting the modification of asphalt using elastomers such as styrene-Butadiene-Styrene block copolymer (St-Bu-St), thermoplastics such as atactic polypropylene and thermoplastic polyolefins.

U.S. Patent Application 2004/0009319 presents a reflecting material of the infrared radiation that is applied directly to the bituminous surface of a product on the roof to increase the reflectance of the solar heat of the product, even when roofing granules are used deep tone to color the product.

U.S. Patent Application 2004/0009319 provides a coating composition useful for building material products, especially for roofing surfaces. The composition of the coating provides a durable external protection to the surfaces to which it is applied, and has intumescent and reflective properties. The coating composition includes a mixture of a polymeric binder, at least one intumescent agent, a polymer carrier, and a pigment. The pigment is present in the coating composition in an amount that is capable of providing a coating that has an initial energy efficiency index greater than or equal to 0.65 for a low slope roof, or an initial energy efficiency greater than or equal to 0.25 for a steeply sloped roof. The coating composition has a solids content of about 30-80%.

U.S. Pat. Nos. 5,002,624; 5,258,222; 5,675,954; 6,408,593; 9,404,259 and the patent applications of the same country 2003/0082365 and 2004/0019150, also use recycled rubber, but their polymeric binder composites are different and do not have thermochromic pigments that match the properties of the present invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the structure of the roof-tile prefabricated covering object of the present invention wherein (1) is a cellulose laminate, (2) is a conglomerated synthetic rubber layer with a thermosetting acrylic resin, and (3) an acrylic coating of thermochromic character;

FIG. 2 shows the chemical structure of the thermosetting resin used as a binder agent in the manufacture of the roof tile object of the present invention, where R₁ and R₂ are C₁-C₁₈ unsaturated acetyl alkyl groups.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a coating functionally equivalent to the asphalt coatings, but with additional performance attributes such as impact resistance, an improvement in thermal resistance, and the integration of more durable and UV resistant materials.

The present invention shows a prefabricated multi-layer roof tile covering comprising a polymeric composite layer having a synthetic rubber (2) obtained from wasted automotive tires, virgin rubber, or from the combination of both, a thermal-retractable acrylic binder, a secondary polymeric cover (3) constituted by an acrylic or vinyl acrylic resin and pigments, from which a thermochromic pigment is contemplated which provides the ability to change color in the range of 20 to 35° C.

In detail, the tile-type prefabricated coating of the present invention includes a multilayer element as shown in FIG. 1. The multilayer element is comprised of a first lower layer made of a laminated cellulosic material (1), which serves as a processing support during the manufacture thereof, an intermediate layer (2) including a film of 2 to 8 mm of a polymeric composite made of crushed synthetic rubber, which is bonded with a thermosetting resin of chemical functionality according to that established in the FIG. 2, and a third layer (3) that is in the upper part and is made of a resin with thermochromic effect that is comprised of a resin or mixture of resins of acrylic, styrene-acrylic, or vinyl-acrylic chemical nature that integrates a charge of pigments such as calcium carbonate, titanium dioxide, and especially an encapsulated pigment of thermochromic material with a transition temperature in the range of 20-35° C. that changes color from white in conditions of high temperature, that is to say, 35° C. or greater to dark in conditions of low temperature, that is to say, 20° C. or smaller. The dark color for the purposes of the present invention is that it is capable of absorbing radiation in the range of the infrared (IR) spectrum.

The cellulosic material layer (1) is comprised of a sheet of cellulose, which is a laminar element of kraft or bond type paper, depending on the needs of the application.

The polymer composite of synthetic rubber (2) includes a conglomerate of synthetic rubber obtained from grounded wasted automotive tires, virgin rubber, or a combination of both, to a mesh in a range of 0.05 to 3 mm in average diameter, mixed with a thermosetting resin or a thermal-retractable acrylic binder which is mainly comprised of a compound of chemical functionality equivalent to that shown in FIG. 2, which is a polyunsaturated macromonomer of glyceryl alkyl ester acrylate (GAEA).

In the manufacturing process, the polyunsaturated macromonomer of GAEA is accompanied by at least one of the following acrylic monomers: methyl methacrylate, ethyl acrylate, acrylic acid, butyl acrylate, styrene, vinyl acetate and acrylonitrile, butyl methacrylate, ethyl methacrylate, and C₁-C₁₈ alkyl acrylates, in order to confer mechanical properties favorable to the specific application in terms of climate where the prefabricated tile-like coating of the present invention will be employed. The polymer composite of synthetic rubber (2), is characterized by having high impact resistance and superior thermal resistance to traditional asphalt coatings.

The resin with thermochromic effect (3), is constituted by a resin that can be of acrylic character, vinyl-acrylic, styrene-acrylic, or combinations of the above, to which is integrated a thermochromic pigment of high resistance to UV radiation whose dark absorption transition from high absorption to infrared to white spectrum, is in the range of 20 to 35° C. The dark color at temperatures lower than 20° C., allows to modulate the thermal absorption of the resin with thermochromic effect and to place it in a high level of heat absorption improving the heat transfer and returning to the prefabricated tile-like coating of the present invention a means of heat capture when the ceiling temperatures are 20° C. or lower.

On the other hand, the transition to white color occurs when the temperatures are higher than 35° C., in this state, the prefabricated tile-like coating of the present invention modulates the capacity of absorption of heat to a state of maximum reflectance by reducing the capacity of transferring heat, thereby increasing the thermal resistance and positioning the prefabricated tile-like coating of the present invention to a state of thermal insulation. These thermal modulation effects allow the tile type prefabricated coating of the present invention to modulate the temperature of home interiors or constructions in general.

The prefabricated tile-type coating of the present invention can be manufactured in different geometries by pultrusion, including the traditional ones: a form of tiles or shingles (by their English denomination), and rolls.

EXAMPLES Example 1

Integrate synthetic rubber with an average particle size of 2.5 mm, polyunsaturated macromonomer of GAEA, styrene and Benzoyl peroxide in a batten mixer with the amounts described in Table 1, and mix at a speed of 40 to 100 rpm for a period of 15 minutes, until achieving the complete integration of the components in a homogeneous paste.

Feed the paste produced to a dosing unit of an endless screw connected to a pultrusion dice set at an inside temperature of 180° C. The pultrusion dice is also fed with kraft paper of 91.5 cm wide and 200 g/m² by the lower part of the dice; this paper serves as a transport element of the paste.

Pull the kraft paper through a traction roller while the paste is fed simultaneously to the pultrusion dice set at 180° C. at a speed that allows the mixture to have a residence time in the pultrusion roller for at least 40 seconds.

Introduce it into an exit of the pultrusion dice, the composite of synthetic rubber obtained in a continuous roller system where a mixture of vinyl acrylic resin that integrates 70% by weight of the thermochromic pigment applied on the surface, generating a surface film of 0.5 to 1.5 mm of thickness, to then pass to a drying oven set at 140° C. that allows drying the mixture of resin and thermochromic material, thus producing a prefabricated coating of thermochromic elastomeric composite.

TABLE 1 Formulation of the elastomeric composite produced in Example 1. Component Quantity (kg) Recycled Synthetic Rubber, Dp = 2.5 mm 60 Macromonomer of Glyceryl Ester Acrylate 15 Styrene 5 Benzoyl peroxide 4

Example 2

Integrate the synthetic rubber with an average particle size of 2.5 mm, polyunsaturated macromonomer of GAEA, butyl acrylate and Benzoyl peroxide in a batten mixer with the amounts described in Table 2, and mix at a speed of 40 to 100 rpm for a period of 15 minutes, until achieving the complete integration of the components in a homogeneous paste.

Feed the paste produced to a dosing unit of an endless screw connected to a pultrusion dice set at a temperature of 180° C. inside. The pultrusion dice is also fed with bond paper of 91.5 cm wide and 200 g/m² for the lower part of the dice; this paper serves as a transport element for the paste.

Pull the bond paper using a traction roller while the resin is fed simultaneously to the pultrusion dice set at 180° C. at a speed that allows the mixture to have a residence time at the pultrusion roller of 30 seconds as a minimum.

Introduce at the exit of the pultrusion dice, the composite of synthetic rubber obtained in a continuous roller system where a mixture of vinyl acrylic resin that integrates 70% by weight of the thermochromic pigment is applied on the surface generating a surface film of 0.5 to 1.5 mm thick.

Go to a drying oven set at 140° C. which allows the mixture of resin and thermochromic material to dry, thus producing a prefabricated thermochromic elastomeric composite coating.

TABLE 2 Formulation table of the elastomeric composite produced in example 2. Component Quantity (kg) Recycled Synthetic Rubber, Dp = 2.5 mm 60 Macromonomer of Glyceryl Ester Acrylate 15 Butyl Acrylate 2 Methyl methacrylate 3 Benzoyl peroxide 4 

1. A synthetic rubber tile with thermal resistance modulation comprising: a multilayer element including: a first layer made of a laminated cellulosic material (1), the first layer serves as a support layer; an intermediate layer (2) made by a film of 2 to 8 mm, made of a crushed synthetic rubber polymeric composite bonded with a thermosetting resin; and a third layer (3) made of a thermochromic resin or mixture of resins selected from the group consisting of an acrylic, styrene-acrylic, or vinyl-acrylic and including a pigments such as calcium carbonate, titanium dioxide, and a thermochromic encapsulated pigment with a transition temperature in the range of 20-35° C., the thermochromic encapsulated pigment changes color from a white color under temperatures of 35° C. or above to dark color in conditions of low temperatures, of 20° C. or less; the dark color is capable of absorbing radiation in the range of the infrared (IR) spectrum.
 2. The synthetic rubber tile according to claim 1, wherein the first layer (1) includes a sheet of cellulose including, a sheet of kraft or bond paper.
 3. The synthetic rubber tile according to claim 1, wherein the intermediate layer (2) includes a conglomerate of synthetic rubber obtained from the waste of automotive tires grounded to a mesh in an interval of 0.05-3 mm of average diameter and the thermosetting resin is a thermal-retractable acrylic binder including a polyunsaturated macromonomer of glyceryl alkyl ester acrylate (GAEA).
 4. The synthetic rubber tile according to claim 3, wherein the polyunsaturated macromonomer of GAEA is accompanied by at least one of the following acrylic monomers: methyl methacrylate, ethyl acrylate, acrylic acid, acrylate butyl, styrene, and vinyl acetate.
 5. The synthetic rubber tile according to claim 1, wherein the crushed synthetic rubber polymeric composite (2) has a high impact resistance and superior thermal resistance to an asphalt.
 6. The synthetic rubber tile according to claim 1, wherein the thermochromic resin (3) includes a resin of acrylic, vinyl-acrylic, styrene-acrylic or combinations thereof.
 7. The synthetic rubber tile according to claim 1, wherein the multilayer element is a root tile or a shingle.
 8. The process of manufacturing the synthetic rubber tile according to claim 1, the method comprising the steps of: a) integrating the synthetic rubber with an average particle size of 2.5 mm, polyunsaturated macromonomer of GAEA, styrene or butyl acrylate and benzoyl peroxide in a batten mixer, and mixing at a rate of 40 to 100 rpm for a period of 15 minutes to form a homogeneous paste; b) feeding the paste to a screw-type dosing unit connected to a pultrusion dice set at an internal temperature of 180° C., the pultrusion dice is also fed with kraft paper through a lower part of the dice, the paper serves as a transport element for the paste; c) pulling the kraft or bond paper by using a traction roller while the paste is fed simultaneously to the pultrusion dice set at 180° C. at a speed that allows the mixture to have a residence time in the pultrusion roller of at least 40 seconds; d) introducing into an exit of the pultrusion dice the composite of synthetic rubber obtained in a continuous roller system where a mixture of vinyl acrylic resin integrates 70% by weight of the thermochromic pigment applied on the surface, generating a surface film of 0.5 to 1.5 mm thick; e) moving the paste to a drying oven set at 140° C. which allows the mixture of resin and thermochromic material to dry, thus producing a prefabricated thermochromic elastomeric composite coating. 